No experienced EOD tech would flip a switch on in a building with confirmed explosives. If he needed more light, Lana should have given him her flashlight, or called for portable lights.
No EOD tech is going to just walk up and grab a door handle on a car like Lana did. They would look it over for explosives top to bottom first.
Cutting through both wires of the power cable to the detonator at the same time (as Nuts does) shorts the two conductors together and would potentially cause the bomb to go off. (You can see this happen when the spark comes off the cutters.) A proper technician would cut the conductors separately.